Graphene is generally understood to be a pure carbon substance that is an allotrope of carbon whose structure is a single planar sheet of sp2-bonded carbon atoms packed in a honeycomb crystal lattice structure. Graphene nanoribbons (GNRs) are ultra-thin lines of graphene. Since graphene exhibits properties such as high carrier mobility, GNRs have been considered for use in high-performance electronic devices, including devices requiring particularly long electrical conductors (e.g., with lengths of one mile or longer). One manner of fabricating GNRs is unzipping carbon nanotubes. However, given their ultra-thin nature, obtaining particularly long GNRs in this manner without encountering breaks, cracks or other discontinuities has proven challenging.